Heating unit



July 24, 1923.. 1,463,005

W. H. DAL-[ON HEATING UNIT Filed Nov. l, 1921 2 Sheets-Sheet l @A e. n

Invenor.

Wiiliam H. Dclhon byfmm w Anya.

July 24, 1923. 1,463,005

W. H. DALTON HEATING UNIT Filed NOV. l, 1921 2 Sheets-Sheef, 2

Inventor. William H. Dol'ron Patented July 24, 1923.

PATENT OFFICE.

WILLIAM H. DAILOIN',V @F SALEM, MASSACHUSETTS.'

HEATEENG UNIT.

Application filed November To aZZfww/m. t may concern.' z

Be it known that I, WILLLAM H. DALTON, a citizen of the United States,and resident of Salem, county of Essex, State of Massachusetts, haveinvented an Improvement in Heating Units, of which the followingdescription, in connection with the accompanying drawing, is aspecification, like characters on the drawing representing like parts.

rlhis invention relates to electric heating units and particularly toheating units et that type which are inthe form of an elongatedcylinder.

@ne of the objects of the invention is to provide a novel heating unitet this type which contains no metal except resistance wire so that theunit will heat metallic parts without danger of short-circuiting theheating current.

Another object of the invention is to provide a heating unit of thistype in which the heating coil 1s connected to the lead wires withoutthe use of binding screws or other metallic elements and in such a waythat the coils themselves are entirely relieved of any strain to whichthe lead wires may be subjected.

Another object of the invention is to provide an improved heating unitwhich is so constructed that the heating coils may be either connectedup in series or in parallel or in other ways to provide a unit or" thewattage desire.

Other objects otI the invention are to provide an improved heating unitwhich has various other advantages all as will be more itullyhereinafter set forth.

lin order to give an understanding of the invention l have illustratedin the drawings some selected embodiments lthereof which will now bedescribed after which the novel features will be pointed out in theappended claims.

, Fig. l is a longitudinal sectional view of the shell or holder ot myimproved heating unit.

Fig. 2 is a perspective view ot the shell.

Fig. 8 is-.an end view..

Fig. 4 shows the heating coil as it is prepared for introduction intothe shell.

Figs. 5 and 6 show the manner in which the heating coil is electricallyconnected to the lead wires and the latter connected to il, 1921. SerialNo. 512,680.

the shell in making up a heating unit having the lead wires extendingfrom opposite ends thereof.

lligs. 7 and 8 show the manner in which these operations are carried outin making a heating unit in which the lead wires extend from the sameend.

Fig. 9 shows an embodiment of the invenipn where the coils are arrangedin paral- Fig. l shows an embodiment of the invention where two or moreheating units are arranged in tandem.

My improved heating unit comprises a shell or holder l which ispreferably cylindrical in shape, although the exact shape is notessential to the invention. This shell or holder l is made oi materialwhich has insulating properties and which is also highly refractory andis a conductor of heat. rlhe shell l is provided with one or morelongitudinal bores 2 extending from one end to the other thereof and inwhich the heating coils may be placed. rllhe shell is also provided witha recess 3 at each end with'which the bores 2 communicate, each recesshaving a sufficient diameter so that all the bores 2 may open thereinto.The formation ot this recess provides a iiange portion 4 at each end ofthe shell which constitutes the wall oiC the recess.

ln the construction illustrated the shell is provided with fourcoil-receiving bores 2 although the number is immaterial so 'far as theinvention is concerned and may be varied without departing therefrom.

rlhe heating coil ot the unit is indicated at and the lead wires at 6.'lhe bores 2 are utilized both for securing the lead wires to the shelll and tor the reception of the heatinO' coil or coils 5.

ln order that the heating coils 5 may function properly it is essentialthat the turns thereof should be correctly spaced and to provide formaintaining this spacing both while the coils are being introduced intothe bores and while the unit is being used l propose to provide astrand-receiving member which extends thevlength of the coil and whichtakes any longitudinal strand thereor". This strand-receiving member isshown at 7 and may be in the form of a cordl or dexible connectionpreferably of insulating `opposite ends of the same bore.

material and which is connected at its ends to the ends of the coil asshown at 8. With this arrangement any longitudinal strain will be takenby the member 7A and not by the coil. f

In assembling the coil 5, lead wires 6 and shell l to make a completeunit I propose to first anchor the end of the lead wires in one or moreof the bores 2 and then to draw the coil through another bore or boresand subsequently connect the ends of the coils to the leadwires.

Figs. 5 and 6 show how this may be done in the case of a unit where thelead wires extend from opposite ends thereof. The lead wires 6 are shownas stranded wires, preferably untwisted stranded wires, and

"one end 9 of each wire is inserted into the end of one ofthe bores 2,as shown in Fig. 5. If the lead wires extend from opposite ends of theunit then the two ends 9 of the lead wires may beinserted into Theselead wires are anchored in the bore in some suitable way as for instanceby filling the latter with cement 10 and in order to make a goodconnection the end of each lead wire may be bent or shaped to form anenlarged' portion 11. The ends of the lead wires are separated from eachother so there is no' electrical connection between them. After the leadwires have been thus anchored in the shell 1 then the coil 5 is drawninto another bore as shown in F ig.l 5. The coil is made with straightends 12 of considerable length and the coil portion thereof will be of alength equal to that of the bore '2. The presence of the connection 7enables the heating unit to be drawn into the bore Without disturbingthe relative position -of the turns of the coil.

After the heating unit has been located in the bore, as shown in Fig. 5,then the ends 12 thereof are twisted with the projecting ends of thelead wires so that a stranded wire is formed in which some of thestrands pass into the end 'of a bore and terminate therein and anotherstrand extends through the bore and constitutes the circuit for theheating current. If desired, the strands of the lead wires 6 may be ofthe same material as that used in the coil 5 or they may be of differentmaterial so long as they have proper conducting properties. i

After the ends of the coil have thus been twisted into the strands 6then suitable insulation 13 is applied to the projecting ends as shownin Fig. 6, the insulation extending clear into the recesses 3. i

A heating unit having this construction has an exterior formed entirelyof insulating material so that it can be used in any location and placedin direct contact with any object without danger of short circuiting theheating current. The only metallic portions of the unit are the leadwires 6 and the coil 5 and these are thoroughly protected by insulation.

In Figs. 'T and SVI have shown an embodiment of the invention where boththe lead wires extend from the same end of the unit. vThe process ofmaking the unit, however, is substantially as above described. that is,the ends of the untwisted stranded lead wires are inserted into the endsof two bores 2 and secured therein, shown in Fig. 7 and the coil 5 isthen drawn through one bore and back through another bore and the endsl2 thereof are then twisted into the lead wires. Insulation is thenapplied to the twisted wires thus producing a heating unit in which thetwo lead wires extend from the same end and in which a double heatingcoil is used with the twol turns thereof in series.

In Fig. 9 I have illustrated an embodiment of the invention in which twocoils 5 are used to be arranged in multiple. The construction of Fig. 9is similar to that shown in Figs. 5 and 6 except that there are twolheating Acoils instead of one and the ends of both coils are twistedinto the leadwires 6.

In Fig. 10 I have shown a different ar rangement in which two shells arearranged in tandem from end to end and' in which longer heating coil isdrawn through both shells thus producing a heating unit of doublelength. In other respects the construction shown in Fig. 10 is similarto that above described.

I claim.

1. Av heating coil comprising ar shell of insulating material having arelatively small bore extending from one end to the other thereof, aheating coil within said bore, a lead wire connected to each end of theCoil outside the bore, and means other than the coil for anchoring eachlead wire to the shell.

2. Ina heating unit, the combination with a shell of insulating materialhaving a bore extending from one end to the other thereof, each end ofthe shell being provided with a recess with which the bore communicates,of a heating co'il within said bore, a lead wire connected to each endof the coil within one of the recesses, and means other than tnleucoilfor anchoring each .lead wire to the s e 3. A heating unit comprising ashell of insulating material having a bore extending from one `end tothe other thereof, two lead wires anchored lto the shell, and a heatingcoil occupying said bore and having each end twisted into an extendedportion of one of the lead wires.

4C. A heating unit comprising a shell of insulating material having vabore' extending therethrough, two lead wires anchored to the shell, aheating coil occupying said here and having each end twisted into anextended portion of one of the lead wires, and insulation covering theportions of the lead wires with which the ends of the heating coil aretwisted.

5. A heating unit comprising a shell of insulating material having aplurality of hores extending from one end to the other thereof9 'twolead wires each having its end entering and anchored in one of thebores, a heating coil occupying another bore and having its H. DALTON.

